In general, a real time performance system must immediately modify or change operation based on change in the surrounding environment. Furthermore, in a hard real time performance system, immediacy is more required than in a system in which the real time performance is required.
In this case, in a control system for mechatoronics equipment such as an industrial equipment or a robot, in order to maintain performance and safety of the mechatoronics equipment, the hard real time performance is required. Briefly, in the control system of the mechatoronics equipment, a permissible time from occurrence of a predetermined event to processing of the event is very short.
Accordingly, in the control system of the mechatoronics equipment, in order to maintain the hard real time performance, a main control apparatus and a plurality of equipments each controlled by the main control apparatus are connected by a leased signal line set to each equipment. Concretely, a control signal including a broadcast signal or an interrupt signal is transmitted through the leased signal line of each equipment. For example, this technique is disclosed in the following two references.
(1) Journal of the Robotics Society of Japan, Vol. 20, No. 1, pp. 89˜97, Zhang et al. “Mathematical Model for Binocular Movements Mechanism and Construction of Eye Axes Control System”
(2) Electronics technology, Vol. 44, No. 4, pp. 14˜18, “A characteristic of ultrasonic motor and its driving•control technology”, Kenichi Kataoka
However, in recent control systems for mechatoronics equipment, the control system is comprised of a large number of equipments because a high level function and a high performance are required. On the other hand, in the control system of the mechatoronics equipment, a main control apparatus and a plurality of equipments each controlled by the main control apparatus are connected by a leased signal line of each equipment. Accordingly, in the control system of mechatoronics equipment, a large number of signal lines are necessary in proportion to a number of equipments connected to the main control apparatus. As a result, the large number of signal lines is in the way to realize a miniaturization, a low price, and a portability of the mechatoronics equipment.